Smolt Trapping & Tagging

The traps were in operation from the end of March until mid-June. The Beltie trap caught 1,300 salmon and over 4,700 trout, whilst the Sheeoch caught 950 salmon and 1,150 trout. By dye-marking some of the smolts, we were able to carry out mark-recapture tests to determine how efficient the traps were at capturing migratory fish. This autumn, the work to calculate total smolt production will be completed and be used as part of this year’s juvenile stock assessment. We will be redeploying the smolt traps at the beginning of September to assess autumn parr migrations.

Smolt tracking

The receivers were finally removed from the Harbour in late July and so the analysis of the data has only just begun. Out of the 50 fish that were tagged, 46 were detected by the receivers. However, there is a large amount of data to review, as these 46 fish were detected by the receivers in total more than 30,000 times! The picture emerging is that there was a higher-than-expected ‘loss’ of fish in the lower river – 24%, but no losses in the inner harbour. The tracking equipment appeared to work very well even in the noisy harbour environment and the team are confident that the equipment has given them the full picture. The large task of interpreting this data is now underway.

The planning of the tracking work for next year is currently underway and is likely to involve tagging and tracking smolts from the upper catchment as well as from the Beltie and Sheeoch traps again. Marine Scotland Science have also outlined a project to look at tracking Dee smolts out with Aberdeen Harbour next year.

​With the news and social media rife with the invasion of Pacific pink salmon, we want to give people an update on the situation on the Dee and what we are doing about it. The situation has developed rapidly in the last month.

As a charity, the River Dee Trust has to raise funds to support its work on the River Dee. We have been humbled by the level of support throughout the year. In the last couple of months, we have had two fundraising events, which have raised £11500, all thanks to the community and River Dee family.

The smolt tagging and tracking project is a three year programme of work. Fifty smolts, captured in the lower catchment, were fitted with internal acoustic tags and tracked in spring 2016. These smolts were tracked as they migrated through the lower 22 miles of the Dee and inner harbour.

Tackling invasive non-native plants along the banks of the River Dee – such as Japanese knotweed, giant hogweed, Himalayan balsam and North American skunk cabbage - has become a priority for the River Office because of their potential impact on our river and its existing, native species.